(1) Field of the Invention
The present invention relates to a tool that can be used by craftsmen to determine the levelness of workpieces and associated surfaces, and more particularly to pivoting adjustable carpenter's levels. The novel tool comprises two segments (sections) that are hingeably attached and can be rotated laterally in the plane of the level so as to be oriented with respect to each other at angles from 0 to 180 degrees. This rotation mechanism extends the effective length of the tool by a factor of 2 and it permits measurement of levelness of two or more workpieces which intersect at angles of up to 180 degrees.
(2) Description of Related Art
Craftsmen, such as carpenters, plumbers, electricians, masons, contractors, and even the occasional handyman, make use of certain basic tools in their jobs. Some of the most common tools are levels, squares, straight edges and measuring devices, among others. Such tools have been around for years. Indeed, some have been around for centuries, and many variations, modifications and improvements have been made.
There have also been numerous attempts to combine the functions of several of these commonly used tools into one tool for convenience. E.g., various “square levels” have been described which can function as a level or as a square. United States Patent Number (“U.S. Pat. No.”) 120,675, issued to Shelley on Nov. 7, 1871, discloses a square level in two parts (sections, each of which is a spirit level) that are hinged to let the two parts move laterally so as to be oriented with respect to each other at an angle of 90 degrees, and then secured by a hook or other suitable locking device to form a square. Each of the two parts shown in the '675 patent are beveled at one end at an inclination of 45 degrees; and, at the two ends thus formed, a hinge is arranged by which the two parts are secured together and rotate to form the 90 degree angle. Shelley states that if a long level is desirable, the two parts may be opened to bring them in line with each other and thus have a level double the length of one of the parts. A square level is also described in U.S. Pat. No. 732,827, issued to Chambers on Jul. 7, 1903. Chambers discloses a hinged level whose two parts can move vertically so as to be oriented with respect to each other at angles from 0 to 90 degrees. Another square level was disclosed in U.S. Pat. No. 1,210,379, issued to Dvorak on Dec. 26, 1916. Dvorak's tool comprised a hinged level that allowed the two parts (sections, each of which was a spirit level) to move laterally with respect to each other at angles of 0 to 90 degrees. Many other patents have issued in the United States since Shelley, Chambers and Dvorak showing levels with sections that are designed to move with respect to each other to form a square.
The carpenter's level is well known to carpenters and other craftsmen. The carpenter's level is usually a single unit that is manufactured in different lengths. Levels in two foot and four foot lengths are common today, but many are shorter (e.g., 6 to 9 inches) and many are substantially longer (e.g., up to 10 to 12 feet). The front and back of the carpenter's level normally has a rectangular configuration, and the top and bottom of the level are likewise rectangular. The width of the carpenter's level can vary, but it is usually about one inch. The top and bottom of the level are smooth flat surfaces with straight edges. The levels contain at least one tubular spirit vial containing a leveling bubble, and normally two or more, so that the user can determine the levelness of a surface and also the plumb, and in some cases a tubular spirit vial is provided to measure other angles as well. The levels historically were made of wood but recent tools are typically made of aluminum, magnesium or other light-weight durable metal. In addition, the body of the carpenter's level usually has handholds carved into the body, or various apertures have been made, to make the tools easier to hold and manipulate. Most of today's levels are designed in an I-beam configuration (from a cross sectional view), and have two or more tubular spirit vials, each of which is located in an aperture in the body of the level so that the leveling bubble in the vial can be viewed from the front or the back of the level. In addition, they generally have one or more apertures for handholds, and many have protective end caps (usually made of a plastic material, such as polypropylene, nylon, or the like). Carpenter's levels are very useful and very basic tools.
Just as craftsmen found it useful to combine the functions of various tools to make them more compact and versatile, various attempts have been made to find a way to make the carpenter's level more compact and versatile. Many of these attempts have focused on ways of altering the length of the device. The shorter levels are typically easier to carry and store, but sometimes a longer level is needed for quality purposes. Some craftsmen modified the tool by designing modular sections that could be combined to make the level longer. See, for example, U.S. Pat. No. 1,132,318; U.S. Pat. No. 1,605,604; and U.S. Pat. No. 1,655,766 to name but a few early patents on the topic. Others used telescoping techniques to make the level longer or shorter, as needed. See, for example, U.S. Pat. No. 4,130,943; U.S. Pat. No. 4,928,395; U.S. Pat. No. 5,412,875; and U.S. Pat. No. 5,577,327 to name but a few patents on the topic. Still others have made levels having a body portion and extendable members that are rotatably attached to each end of the body portion. See, for example, U.S. Pat. No. 4,813,149.
However, the need still exists for a carpenter's level that can be easily extended in length when needed for longer surfaces, and contracted when needed for shorter surfaces. A need also exists for a carpenter's level that can be used to measure the levelness of intersecting surfaces. These needs are met by the present invention.